1. Field of the Invention
The invention relates to paper drive apparatus generally referred to as a paper drive tractor and more specifically to locking means operably associated with such paper drive tractor apparatus for securing or immobilizing the drive tractor in a pre-set position relative to an associated tractor and/or the fanfold paper with which it is to be utilized.
2. Prior Art
Fanfolded paper utilized with machine data processing apparatus, particularly printers and stackers, carry parallel edge perforations which are engageable by solid projecting elements carried by driving units called "tractors". Such tractors are generally positioned on opposite sides of the fanfolded sheet of paper so that the driving elements of the tractor project into and through the perforations of the paper. As the tractor is energized or cycled, the projecting elements, usually carried on belts driving by wheels from a main drive of the associated data processor, are caused to push or pull the paper across the print head and/or into a stacking bin as the case may be.
Such tractors must be movable laterally so as to accommodate the drive to various widths of fanfolded paper. Also the tractor must be capable of being fixedly secured in position once the width has been adjusted for.
In certain types of apparatus it is more efficient and convenient to adjust only one of two tractor devices, the other tractor remaining fixed in a preadjusted position. Various types of locking devices have been proposed and employed in the past, each more or less specialized for the specific application under consideration. Each type has had its own limitations and no one type fills are requirements.
The presently disclosed tractor locking apparatus permits the tractor to be employed in an environment wherein it is desired to have one tractor remain fixed in position while the oppositely disposed tractor is movable so as to accommodate various widths of fanfolded paper. Although the locking apparatus conceivably could be employed on both tractors making any position available for either tractor, the locking element of the present invention is quick, sure, simple and efficient and relatively inexpensive to fabricate. And, by virtue of the novel mechanical arrangement, the present invention provides a quick release and securement position.